Washing machine

ABSTRACT

The present invention provides a washing machine, by which washing and dewatering capabilities are enhanced. The present invention includes a housing, a tub provided within the housing to reserve water therein, a drum rotatably provided within the tub to perform washing on a laundry therein, and at least one lifter projected on an inner circumference of the drum at a first predetermined height to lift the laundry to fall from a second predetermined height wherein the laundry is prevented from being stuck between one side of the at least one lifter and the drum.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Applications Nos.P03-51958, filed on Jul. 28, 2003, and P03-51959 filed on Jul. 28, 2003which are hereby incorporated by reference as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a washing machine, and moreparticularly, to a lifter installed in a drum of a washing machine.

2. Discussion of the Related Art

Generally, a washing machine is an apparatus for washing a laundry byrotating a drum holding a detergent, water, and laundry therein. Awashing machine generally includes a tub and a drum rotatably installedwithin the tub to perform washing using the tub and drum. The tubpreliminarily stores water therein, and the drum to which the water anddetergent are supplied is rotated together with the laundry therein.Moreover, a plurality of lifters are installed within the drum. Thelifters rotating together with the drum lift the laundry to apredetermined height to drop. Besides, washing is performed on thelaundry using the chemical reaction between the water and detergent aswell as mechanical shock & friction by the drum and lifters.

In such a general washing machine, the drum is rotated at high speedwhen dewatering is performed on the laundry. A centrifugal forcegenerated from the high-speed rotation makes the laundry adhere closelyto an inner circumference of the drum uniformly.

However, the laundry tends to be stuck in a space between a side of thelifter and the inner circumference of the drum in the vicinity of theside of the lifter. In such a case, the laundry fails to be spreaduniformly on the inner circumference of the drum but to be raveled,whereby the watering fails to be completed. And, it is difficult to pullthe raveled laundry out of the drum after completion of the dewatering.

Moreover, the drum is rotated at low speed during washing or rinsingcycle, whereby the laundry fails to be sufficiently contacted with bothsides of the lifter. Hence, the friction generated between the laundryand the lifter is not enough to enhance washing performance.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a washing machine thatsubstantially obviates one or more of the problems due to limitationsand disadvantages of the related art.

An object of the present invention, which has been devised to solve theforegoing problem, lies in providing a washing machine, by which alaundry is uniformly spread on an inner circumference of a drum.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent to thosehaving ordinary skill in the art upon examination of the following ormay be learned from a practice of the invention. The objectives andother advantages of the invention will be realized and attained by thesubject matter particularly pointed out in the specification and claimshereof as well as in the appended drawings.

To achieve these objects and other advantages in accordance with thepresent invention, as embodied and broadly described herein, there isprovided a washing machine including a housing, a tub provided withinthe housing to reserve water therein, a drum rotatably provided withinthe tub to perform washing on a laundry therein, and at least one lifterprojected on an inner circumference of the drum at a first predeterminedheight to lift the laundry to fall from a second predetermined heightwherein the laundry is prevented from being stuck between one side ofthe at least one lifter and the drum.

The at least one lifter includes an extension extending from one of bothlateral sides along the inner circumference of the drum. Preferably, theat least one lifter includes an extension extending from one of bothlateral sides in a main rotational direction of the drum. Specifically,the main rotational direction of the drum is a rotational directionduring dewatering.

The extension includes at least one hole communicating with at least oneor more perforated holes of the drum to have the water flow in via theextension. Preferably, an entrance of the hole is configured not to becontacted with the laundry.

The extension includes tops and bottoms alternatively arranged on anupper end of the extension in a length direction of the extension.Preferably, the extension comprises an upper end having a wave shape.Preferably, the extension includes a plurality of holes formed in thebottoms to communicate with at least one or more perforated holes of thedrum. Moreover, the extension includes at least one rib extending on anupper end of the extension in a length direction of the extension.Preferably, the extension includes a plurality of ribs extending inparallel on an upper end of the extension in a length direction of theextension. Preferably, the extension includes holes between a pluralityof the ribs to communicate with at least one or more perforated holes ofthe drum. Besides, the extension includes a plurality of projections onan upper end of the extension to leave a predetermined interval fromeach other. And, the extension includes holes between a plurality of theprojections to communicate with at least one or more perforated holes ofthe drum.

Moreover, a groove extends between the extension and the at least onelifter in a length direction of the extension or the at least onelifter.

Meanwhile, the at least one lifter includes at least one or morerotational bodies rotatably installed to be contacted with the laundry.The at least one lifter includes at least one recess receiving the atleast one rotational body therein to prevent the at least one rotationalbody from being separated from the at least one lifter. Moreover, the atleast one lifter includes at least one hole communicating with at leastone or more perforated holes of the drum to have the water flow in viathe at least one lifter.

By the above-described present invention, the laundry avoids being stuckbetween the lateral side of the lifter and the inner circumference ofthe drum and is evenly spread on the inner circumference of the drum tobe well dewatered. Moreover, the lifter has the increased contact areawith the laundry, thereby enhancing washing capability.

It is to be understood that both the foregoing explanation and thefollowing detailed description of the present invention are exemplaryand illustrative and are intended to provide further explanation of theinvention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIG. 1 is a cross-sectional diagram of a washing machine according tothe present invention;

FIG. 2 is a perspective diagram of a drum of a washing machine accordingto the present invention;

FIG. 3A is a layout of a lifter of a washing machine according to thepresent invention;

FIG. 3B and FIG. 3C are cross-sectional diagrams of the lifter bisectedalong cutting lines I-I and II-II in FIG. 3A, respectively;

FIG. 4A is a layout of a modified lifter body according to the presentinvention;

FIG. 4B is a cross-sectional diagram of the modified lifter bodybisected along a cutting line I-I in FIG. 4A;

FIG. 5A is a layout of another modified lifter body according to thepresent invention;

FIG. 5B is a cross-sectional diagram of another modified lifter bodybisected along a cutting line I-I in FIG. 5A;

FIG. 6A is a layout of a modified lifter extension according to thepresent invention;

FIG. 6B and FIG. 6C are cross-sectional diagrams along cutting lines I-Iand II-Il in FIG. 6A, respectively;

FIG. 7A is a layout of another modified lifter extension according tothe present invention; and

FIG. 7B and FIG. 7C are cross-sectional diagrams along cutting lines I-Iand II-II in FIG. 7A, respectively.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiment(s) ofthe present invention, examples of which are illustrated in theaccompanying drawings. Throughout the drawings, like elements areindicated using the same or similar reference designations wherepossible.

FIG. 1 is a cross-sectional diagram of a washing machine according tothe present invention. A washing machine according to the presentinvention is explained by referring to FIG. 1 as follows. The washingmachine shown in the drawing is a front-loading type having ahorizontally laid tub and drum. The front-loading type washing machinehas the similar structure of a top-loading type washing machine havingan upright tub and drum.

Referring to FIG. 1, a washing machine according to the presentinvention includes a housing 10, a tub 20 installed within the housing10, and a drum 30 installed within the tub 20.

Various parts are installed within the housing 10 to be protected. Adoor 11 is provided to a front side of the housing 10 to be configuredto open/close a housing opening 10 a communicating with the drum 30.Specifically, the housing opening 10 a communicates with a tub opening20 a and a drum opening 30 a in turn to pit a laundry in the drum 30.And, a gasket 12 is provided between the housing opening 10 a and thetub opening 20 a to prevent water leakage. Moreover, a control panel 13is installed on an upper part of the housing 10. A user instructs anoperation of the washing machine using the control panel 13 andputs/pulls the laundry in/from the drum 30 using the door 11. The tub 20reserves water therein to supply the water to the drum 30 uniformly onwashing. A passing hole is formed in a bottom center of the tub 20, anda drive shaft 42 is connected to the drum 30 via the passing hole. Thetub 20 includes a balance weight 21 and is elastically installed withinthe housing 10 using a damper 22 and a suspension spring 23. The drum 23holds 30 a laundry therein and is rotatably installed within the tub 20.The drum 30 includes a multitude of perforated holes 31 via which waterflows in the drum 30 and a lifter 100 for assisting washing. Meanwhile,a drive unit 40 is provided to the tub 20 to provide a drive force forrotating the drum 30. The drive unit 40 includes a motor 41 and thedrive shaft 42 connecting the motor 41 to the drum 30. Specifically, themotor 41 includes a stator 41 a fixed to a bottom side of the tub 20 anda rotor 41 b rotatably installed to enclose the stator 41 a. As therotor 41 b is directly connected to the drive shaft 42, the drive forceof the motor 41 is directly transferred to the drum 30 via the driveshaft 42 without loss of the drive force. Hence, the drive unit 40 isvery advantageous in aspect of efficiency, noise, and vibration.Although not shown in the drawing, the drive unit 40 may include ageneral drive mechanism constructed with pulleys installed at the drum30 and motor and a belt connecting the pulleys.

In the above-explained washing machine, the lifter (baffle) 100 isprovided to an inner circumference of the drum 30 to protrude at apredetermined height. The drum 30 includes at least one or more lifters100. The lifter 100 is prepared as a separate member to be installed inthe drum 30 or may be built in one body of the drum 30 to protrudeinward by ‘pressing’. As the lifter 100 is projected, the laundrybecomes caught on the lifter 100 while the drum 30 is rotated. Thelifter 100 is rotated together with the drum 30 to lift the laundry to apredetermined height. The lifted laundry then falls from the lifter bygravity to collide with another laundry, water, drum 30, or anotherlifter 100. Moreover, the laundry becomes rubbed with the lifter 100during the rotation of the drum 30. Hence, the laundry is moreefficiently washed by the mechanical collision and friction. Besides,the lifter 100 additionally plays a role in stirring the laundry to aidthe washing. The lifter 100 according to the present invention isexplained in detail by referring to the attached drawings as follows.

FIG. 2 is a perspective diagram of a drum of a washing machine accordingto the present invention, FIG. 3A is a layout of a lifter of a washingmachine according to the present invention, and FIG. 3B and FIG. 3C arecross-sectional diagrams of the lifter bisected along cutting lines I-Iand II-II in FIG. 3A, respectively.

Referring to FIG. 2, a lifter 100 includes a main body 110 and anextension 120 connected to the main body 110.

The main body 110 approximately extends in parallel with a central axisof the drum 30 to be frequently contacted with the laundry. The mainbody 110 is preferably formed of a metal or synthetic resin basedmaterial that is resistant against corrosion and abrasion due to wateras well as fails to chemically react with a detergent. Moreover, atleast one rotational body 111, as shown in FIG. 3A, is rotatablyprovided to the main body 110 to be partially projected from the mainbody 110 to be contacted with the laundry. The rotational body 111, asshown in FIG. 3B, is preferably a ball that is optimally rotatable. And,a plurality of rotational bodies 111, as shown in the drawings, arearranged along an upper end of the main body 110. Hence, each of therotational bodies 111 becomes contacted with the laundry to rotate,whereby the corresponding laundry smoothly slides on the lifter 100.Consequently, the laundry avoids being raveled by the lifter 100 owingto the rotational bodies 111 so as not to be entangled with otherlaundries. Moreover, the laundry lifted by the lifter 100 is facilitatedto slide to fall from the lifter at a predetermined height.Specifically, the main body 110 includes at least one recess 110 apreventing the rotational body 11 from being detached from the main body110. As mentioned in the forgoing description, in case that the main by110 includes a plurality of the rotational bodies 111, a plurality ofrecesses 110 a are arranged along the upper end of the main body 110.Moreover, in case that the rotational body 111 is the ball, the recess110 a preferably has a hemispherical shape to enable a smooth rotationof the rotational body 111 and to support a lower part of the rotationalbody 111 stably. Furthermore, the recess 110 a can be processed to havea smooth surface or a separate lubricant coating can be formed on asurface of the recess 11 a. The recesses 110 a, as shown in thedrawings, are built in one body of the main body 110. Instead, it isunderstandable that a separate panel (not shown in the drawings)including the recesses 110 a is coupled to the upper part of the mainbody 110.

At least one hole 110 b, as shown in FIG. 3B, is formed in the main body110 to communicate with the perforated hole 31 of the drum 30. Hence,water held in the tub 20 flows in the drum 30 via the main body 110using the perforated hole 31 and the hole 110 b, whereby efficient watersupply is achieved. For the purpose of more efficient water supply, amultitude of holes 110 b are formed in the main body 110. Since asufficient space is needed to form the holes 110 b, the holes 110 b, asshown in FIG. 3A, are appropriately arranged between the rotationalbodies 111. The holes 110 b, as shown in FIG. 3A, can be arranged thespaces between the rotational bodies 111 in a length direction of themain body 110. Or, the holes 110 b, as shown in FIG. 4A, may be arrangedin a direction perpendicular to the length direction. Moreover, theholes 110 b, as shown in FIG. 5A, can be arranged diagonally in therespective spaces between the rotational bodies 111. In this case, moreholes can be provided to each of the spaces between the rotationalbodies 111. Furthermore, rows of the diagonally arranged holes 110 b, asshown in the drawing, can be zigzagged (staggered) from each other.

Referring to FIG. 4A, the main body 110 may further include a platemember 112 holding the rotational body 111 to prevent from beingseparated from the main body 110. The rotational body 111 can be morestably installed in the body 110 by the plate member 112. The platemember 112 is preferably formed of metal or synthetic resin. The platemember 112 is mounted on the upper end of the main body 110 like therotational body 111 and includes the hole 112 a to have the rotationalbody 111 fitted therein. As mentioned in the foregoing description,since the main body 110 includes a plurality of the rotational bodies111, a plurality of holes 112 a are provided to the plate member 112 tocorrespond to the rotational bodies 111, respectively. The holes 112 a,as shown in FIG. 4B, are formed to confront the recesses 110 a holdingthe rotational bodies 111, respectively. Each size of the holes 112 a issmaller than that of the corresponding rotation body 111, whereby eachof the holes 112 a can hold the corresponding rotational body 111. And,auxiliary holes 112 b are formed in each space between the holes 12 a tocommunicate with the holes 110 b of the main body 110, whereby the wateris supplied to the drum 30 via the main body 110 from the tub 20. Incase that the plate member 112 is projected from the main body 110,damage may be caused to the laundry during washing. Hence, the platemember 112 is preferably formed not to be projected out of the main body110. Specifically, a loading portion, as shown in FIG. 4B, is providedto the upper end of the main body 110 so that the plate member 112 canbe loaded on the loading portion not to be projected. Alternatively, topportions 110 c and bottom portions 110 d, as shown in FIG. 5A and FIG.5B, are formed on at least one side of the main body 110. The top andbottom portions 110 c and 110 d are alternately arranged in a lengthdirection of the main body 110. The top and bottom portions 110 c and110 d increase a contact area of the lifter 100 with the laundry,thereby enhancing washing performance of the washing machine. Thus, thetop and bottom portions 110 c and 110 d are preferably formed on bothlateral sides of the main body 110. More preferably, the top and bottomportions 110 c and 110 d are formed smooth not to cause damage to thelaundry. In such a case, each of the lateral sides of the main body 110has a wave shape. Moreover, the rotational bodies 111 relatively needmore space than the holes 110 b, whereby each of the correspondingrotational bodies 111 is provided between a pair of the correspondingtop portions 110 c of both of the lateral sides of the main body 110 andthe holes 110 b are provided between a pair of the corresponding bottomportions 110 d of both of the lateral sides of the main body 110.

Referring to FIG. 3A, the extension 120 extends from one of both of thelateral sides of the main body 110 along the inner circumference of thedrum 30. The drum 30 is rotatably configured in both forward and reversedirections, i.e. a first direction and a second direction opposite tothe first direction. Yet, the drum 30 tends to mostly rotate in one ofthe first and second directions through the entire cycles of washing,rinsing, and dewatering. The laundry is mainly contacted with the lifter100, and more accurately, with one of both of the lateral sides of themain body 110 oriented in the main rotational direction, therebybecoming stuck in a gap between the corresponding lateral side of themain body 110 and the inner circumference of the drum 30. In order toprevent the laundry from being stuck in the corresponding gap, theextension 120 preferably extends from one of the both of the lateralsides of the main body 110 in the main rotational direction of the drum30. Moreover, even if the drum 30 is alternately rotated in the first orsecond direction during washing or rinsing, the drum 30 is rotated athigh speed in either the first direction or the second direction duringdewatering, whereby the laundry is badly stuck in the gap between thecorresponding lateral side of the main body 110 and the innercircumference of the drum 30. Most preferably, the extension 120 extendsfrom the main body 110 in the rotational direction of the drum 30 fordewatering. Besides, even if the main rotational direction is differentfrom the rotational direction of dewatering, the extension 120 extendsin the rotational direction of dewatering to be more effective inpreventing the laundry from being stuck in the gap between the lateralside of the main body 110 and the inner circumference of the drum 30.Alternatively, in order to completely prevent the laundry from beingstuck in the gap between the lateral side of the main body 110 and theinner circumference of the drum 30, the lifter 100 may include a pair ofextensions 120 extending from both of the lateral sides of the main body110 along the inner circumference of the drum 30, respectively.

Specifically, the extension 120, as shown in the drawings, is shorterthan the lifter 100, i.e., the main body 110. Yet, the extension 120 canbe formed longer than the main body 100 if necessary. If the extension120 is formed higher than the main body 110, the main body 110, and moreparticularly, the rotational body 111 is unable to perform its functionappropriately. Hence, the upper end of the extension 120, as shown inFIG. 3B is provided lower than that of the main body 110 and is properlyplaced at about a half of height of the main body 110. And, a lower endof the extension 120 is contacted with the inner circumference of thedrum 30. Namely, the extension 120 extends from the inner circumferenceof the drum like the main body 10 but has height smaller than that ofthe main body 110. The height f the extension 120 is adjustable ifnecessary. Thus, the lifter 100 according to the present inventioncovers the predetermined gap between the lateral side of the main bodyand the inner circumference of the drum 30. Furthermore, the lifter 100,and more particularly, the extension 120 substantially fills up thepredetermined gap between the lateral side of the main body and theinner circumference of the drum 30. Hence, the lifter 100 isolates thepredetermined gap from other inner space of the drum 30, therebyenabling to cut off the access of the laundry to the predetermined gap.Consequently, the lifter 100 according to the present inventioneffectively prevents the laundry from being struck between the lateralside of the main body 110 and the adjacent inner circumference of thedrum 30.

At least one or more holes 121, as shown in FIG. 3B, are formed in theextension 120 to communicate with the perforated holes 31 of the drum30. Hence, the water in the tub 2 can flow in the drum 30 via theextension 120 using the perforated holes 31 and the holes 121 of theextension 120. Hence, the water can be supplied to drum 30 via theoverall lifter 100, whereby water supply is efficiently performed. Aplurality of the holes 121 are preferably formed in the extension 122for the more efficient water supply. Moreover, a groove 122 is providedbetween the extension 120 and the main body 110 in the length direction.A lateral side, as clearly shown in FIG. 3B, is formed on the extension120 by the groove 122 to increase the corresponding lateral side of themain body 110. Hence, the extension 120 and main body 110 basically havethe increased contact area with the laundry. Besides, the groove 122plays a role in draining the water from the lifter 100 smoothly as well.

The lifter 100 including the extension 120 secures the increased contactarea with the laundry to increase the friction thereof, thereby enablingto enhance washing capability. In order to enhance the washingcapability higher, the extension 120 is preferably configured toincrease the contact area with the laundry more. For this, the extension120 is configured to protrude in part. Specifically, top portions 120 aand bottom portions 120 b, as shown in FIGS. 3A to 3C, are formed on theupper end of the extension 120. The top and bottom portions 120 a and120 b are alternately arranged in the length direction of the extension120. Preferably, the top and bottom portions 120 a and 120 b are formedsmooth not to cause damage to the laundry. In such a case, the upper endof the extension 120 has a wave shape. The top and bottom portions 120 aand 120 b are identically shown in FIGS. 4A to 5B as well.Alternatively, at least one or more ribs 123, as shown in FIGS. 6A to6C, can be formed on the upper end of the extension 120 to extend in thelength direction of the extension 120. Preferably, a plurality of theribs 123 are provided to the upper end of the extension 120 in parallelwith other. Yet, since a size of the upper end of the extension 120 isnot sufficient, a pair of the ribs 123, as shown in the drawings, arepreferably formed on the upper end of the extension 120. Meanwhile, theextension 120, as shown in FIGS. 7A to 7B, may include a plurality ofprojections 124 formed on its upper end to leave a predeterminedinterval from each other. The projections 124 are preferably arranged onthe upper end of the extension 120 in the length direction of theextension 120 to be evenly contacted with the laundry.

Meanwhile, a burr may be formed in the vicinity of an entrance of thehole 121 in forming the holes 121. And, damage may be caused to thelaundry by the burrs. Specifically, the drum 30 is rotated at high speedin the early stage of dewatering so that the laundry vigorously moves.Hence, it is highly probable that such damage will be caused to thelaundry. Preferably, the entrances of the holes 121 are configured notto be contacted with the laundry. The holes 121 are substantiallylocated between the projected portions 120 a, 123, or 124. Specifically,the holes 121, as shown in FIG. 3A and FIG. 3C, are formed between thetop portions 120 a, i.e., on the bottom portions 120 b. And, the holes121, as shown in FIG. 6A and FIG. 6C, are formed between the bibs 123.Moreover, the holes 121, as shown in FIG. 7A and FIG. 7C, are formedbetween the projections 124. Even if the holes 121 are processed rough,the damage caused to the laundry can be minimized.

Accordingly, the washing machine according to the present invention hasthe following advantages or effects.

First of all, the extension prevents the laundry from being entangled orstuck between the lateral side of the main body and the innercircumference of the drum, specifically during dewatering. Hence, thelaundry or laundries are evenly spread on the inner circumference of thedrum to be properly dewatered. And, a user is facilitated to pull thelaundries out of the drum after completion of dewatering.

Secondly, the lifter prevents the laundry from being entangled withother using the rotational body and has the increased contact area withthe laundry using its structural modifications. Therefore, the liftercan be more rubbed with the laundry to enhance washing capability.

Finally, the enhancement of the dewatering and washing capabilitiesincreases user's reliance on the washing machine.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover such modifications andvariations, provided they come within the scope of the appended claimsand their equivalents.

1. A washing machine comprising: a housing; a tub provided within thehousing to reserve water therein; a drum rotatably provided within thetub to perform washing on a laundry therein; and at least one lifterprojected on an inner circumference of the drum at a first predeterminedheight to lift the laundry to fall from a second predetermined heightwherein the laundry is prevented from being stuck between one side ofthe at least one lifter and the drum.
 2. The washing machine of claim 1,wherein the at least one lifter prevents the laundry from accessing to agap between the lateral side of the lifter and the inner circumferenceof the drum.
 3. The washing machine of claim 1, wherein the at least onelifter isolates a gap between the lateral side of the lifter and theinner circumference of the drum from an inner space of the drum.
 4. Thewashing machine of claim 1, wherein the at least one lifter isconfigured to cover a gap between the lateral side of the lifter and theinner circumference of the drum.
 5. The washing machine of claim 1,wherein the at least one lifter is configured to fill up a gap betweenthe lateral side of the lifter and the inner circumference of the drum.6. The washing machine of claim 1, wherein the at least one lifter isconfigured to increase a contact area with the laundry.
 7. The washingmachine of claim 1, wherein the at least one lifter comprises anextension extending from one of both lateral sides along the innercircumference of the drum.
 8. The washing machine of claim 1, whereinthe at least one lifter comprises extensions extending from both lateralsides along the inner circumference of the drum, respectively.
 9. Thewashing machine of claim 1, wherein the at least one lifter comprises anextension extending from one of both lateral sides in a main rotationaldirection of the drum.
 10. The washing machine of claim 9, wherein themain rotational direction of the drum is a rotational direction duringdewatering.
 11. The washing machine of claim 8, wherein the extension isshorter than the at least one lifter.
 12. The washing machine of claim8, wherein an upper end of the extension is lower than an upper end ofthe lifter.
 13. The washing machine of claim 8, wherein an upper end ofthe extension is located at a half of a height of the lifter.
 14. Thewashing machine of claim 8, wherein a lower end of the extension iscontacted with the inner circumference of the drum.
 15. The washingmachine of claim 8, wherein the extension comprises at least one holecommunicating with at least one or more perforated holes of the drum tohave the water flow in via the extension.
 16. The washing machine ofclaim 15, wherein an entrance of the hole is configured not to becontacted with the laundry.
 17. The washing machine of claim 8, whereinthe extension is configured to increase a contact area with the laundry.18. The washing machine of claim 8, wherein the extension is configuredto protrude in part.
 19. The washing machine of claim 18, wherein theextension comprises at least one hole between protrusions of theextension to communicate with at least one or more perforated holes ofthe drum.
 20. The washing machine of claim 8, wherein the extensioncomprises tops and bottoms alternatively arranged on an upper end of theextension in a length direction of the extension.
 21. The washingmachine of claim 8, wherein the extension comprises an upper end havinga wave shape.
 22. The washing machine of claim 20, wherein the extensioncomprises a plurality of holes formed in the bottoms to communicate withat least one or more perforated holes of the drum.
 23. The washingmachine of claim 8, wherein the extension comprises at least one ribextending on an upper end of the extension in a length direction of theextension.
 24. The washing machine of claim 8, wherein the extensioncomprises a plurality of ribs extending in parallel on an upper end ofthe extension in a length direction of the extension.
 25. The washingmachine of claim 24, wherein the extension comprises holes between aplurality of the ribs to communicate with at least one or moreperforated holes of the drum.
 26. The washing machine of claim 8,wherein the extension comprises a plurality of projections on an upperend of the extension to leave a predetermined interval from each other.27. The washing machine of claim 26, wherein the extension comprisesholes between a plurality of the projections to communicate with atleast one or more perforated holes of the drum.
 28. The washing machineof claim 8, wherein a groove extends between the extension and the atleast one lifter in a length direction of the extension or the at leastone lifter.
 29. The washing machine of claim 1, wherein the at least onelifter is configured to have the laundry slide thereon.
 30. The washingmachine of claim 1, wherein the at least one lifter comprises at leastone or more rotational bodies rotatably installed to be contacted withthe laundry.
 31. The washing machine of claim 30, wherein the at leastone rotational body is a ball.
 32. The washing machine of claim 30,wherein a plurality of rotational bodies are arranged along an upper endof the at least one lifter.
 33. The washing machine of claim 30, whereinthe at least one lifter comprises at least one recess receiving the atleast one rotational body therein to prevent the at least one rotationalbody from being separated from the at least one lifter.
 34. The washingmachine of claim 30, wherein the at least one lifter further comprises aplate installed on a surface of the at least one lifter to hold the atleast one rotational body to prevent the at least one rotational bodyfrom being separated from the at least one lifter.
 35. The washingmachine of claim 34, wherein the plate comprises at least one holehaving a size smaller than that of the at least one rotational body tohave the at least one rotational body fitted therein.
 36. The washingmachine of claim 34, wherein the plate is installed not to be projectedfrom the at least one lifter.
 37. The washing machine of claim 1,wherein the at least one lifter comprises at least one holecommunicating with at least one or more perforated holes of the drum tohave the water flow in via the at least one lifter.
 38. The washingmachine of claim 30, wherein the at least one lifter comprises aplurality of holes between the rotational bodies to communicate with atleast one or more perforated holes of the drum.
 39. The washing machineof claim 38, wherein a plurality of the holes are arranged in a rowbetween the rotational bodies.
 40. The washing machine of claim 38,wherein a plurality of the holes are diagonally arranged in each spacebetween the rotational bodies.
 41. The washing machine of claim 1,wherein the at least one lifter comprises tops and bottoms formed on atleast one lateral side to be alternately arranged in a length directionof the at least one lifter.
 42. The washing machine of claim 1, whereinat least one lateral side of the at least one lifter is wave-shaped.